A test pattern can allow a user to troubleshoot, adjust, or calibrate settings of a display device, such as a television set, computer monitor, video receiver, or other device that visually presents information. In the early days of broadcast television, a test pattern was generated by pointing a camera at a test card, and broadcasting the recorded images of the test card. A user could use the broadcast images of the test card to calibrate a television set. Later, images of test patterns were generated by special equipment and broadcast. More recently, a test pattern can be distributed on digital media and played back on a display device, or be stored in onboard memory of a display device and accessed through a settings menu, or even be downloaded and run in a Web browser.
Typically, a test pattern depicts a known pattern of shapes and/or colors, or depicts a sequence of such patterns. For some types of test pattern, a setting of a display device can be tuned, calibrated, or otherwise adjusted while viewing the test pattern or after viewing the test pattern. In many cases, a test pattern will not be displayed correctly until a setting of the display device is appropriately adjusted. In other cases, using a test pattern, a user can tune performance of the display device according to personal preferences. For example, some test patterns for a liquid crystal display (“LCD”) device can allow a user to calibrate various settings, such as contrast, sharpness, saturation, black level, timing (clock, phase), and gamma.
For other types of test pattern, a problem with a display device or characteristic of the display device can be diagnosed, but the display device is not adjusted. Thus, in some cases, display of a test pattern may induce some behavior in a display device that illustrates a problem with the display device, so as to help a user or manufacturer identify and diagnose the problem. As another example, certain test patterns for an LCD device can allow a user to assess features such as viewing angle of the LCD device.